focus 20ltr battery light problem please help
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focus 20ltr battery light problem please help
hi all i just wondered if anyone could shed some light on my problem.
ive just bought a 2000 focus 2ltr petrol and the battery light comes on after 30 seconds of running and stays but the car loses it battery power after 30 miles of drivin its had a new alternator new battery ive checked all the earths and all the fuses theres no sign of any broken wires on the 3 pin plug and now i dont know what to check next any ideas would be more than gratefull thanks for reading
ive just bought a 2000 focus 2ltr petrol and the battery light comes on after 30 seconds of running and stays but the car loses it battery power after 30 miles of drivin its had a new alternator new battery ive checked all the earths and all the fuses theres no sign of any broken wires on the 3 pin plug and now i dont know what to check next any ideas would be more than gratefull thanks for reading
They are equipped with a "Smart Charge" system, most importantly is the battery a "Silver Calcium" type as it is vital it is?
It may be a break in the wiring, rarely is the ECU or smart charge the problem, here is some excellent info on this matter posted by another member:
First things first, check the battery, not just condition, but correct type. A lead acid battery will not work properly with smart charge, it must be Silver Calcium! Easy to over look.
Next, put a meter across the battery. Remember when you remove the smart charge 3 pin plug from the back of the alternator, it reverts to a conventional alternator! If you do not have about 13.8 volts, carry out basic charging system checks and suspect the alternator, its not a smart charge fault !
Correct charge voltage from the alternator, then its time to start on the smart charge system, and you will need a scope. First the system.
Pin 1 = Alternator Feedback
Pin 2 = Alternator Load Request
Pin 3 = Reference Voltage
Now, pin3, must MATCH battery voltage ! Its fed from a fuse in the CJB, and a high resistance on the fuse contacts causes a volt drop, and the smart charge drops out !
Next pin 1 & 2 need checking back to the PCM for resistance, isolation from ground and each other. If ok, its out with the scope.
Pin 2 is the request from the PCM to the alternator. This will be a square wave pattern that will change with load request. So lights, screens etc on and monitor for a change in the pattern. (Obviously back probing with the plug connected)
No change in the pattern means no request from the PCM, you should now suspect a PCM fault. Correct pattern and move on.
Pin 1 is the feedback from the alternator and MUST remain a constant square wave pattern. If this pattern mirrors the one on pin 2, the smart charge part of the alternator is faulty, and a new unit is required.
Martin
It may be a break in the wiring, rarely is the ECU or smart charge the problem, here is some excellent info on this matter posted by another member:
First things first, check the battery, not just condition, but correct type. A lead acid battery will not work properly with smart charge, it must be Silver Calcium! Easy to over look.
Next, put a meter across the battery. Remember when you remove the smart charge 3 pin plug from the back of the alternator, it reverts to a conventional alternator! If you do not have about 13.8 volts, carry out basic charging system checks and suspect the alternator, its not a smart charge fault !
Correct charge voltage from the alternator, then its time to start on the smart charge system, and you will need a scope. First the system.
Pin 1 = Alternator Feedback
Pin 2 = Alternator Load Request
Pin 3 = Reference Voltage
Now, pin3, must MATCH battery voltage ! Its fed from a fuse in the CJB, and a high resistance on the fuse contacts causes a volt drop, and the smart charge drops out !
Next pin 1 & 2 need checking back to the PCM for resistance, isolation from ground and each other. If ok, its out with the scope.
Pin 2 is the request from the PCM to the alternator. This will be a square wave pattern that will change with load request. So lights, screens etc on and monitor for a change in the pattern. (Obviously back probing with the plug connected)
No change in the pattern means no request from the PCM, you should now suspect a PCM fault. Correct pattern and move on.
Pin 1 is the feedback from the alternator and MUST remain a constant square wave pattern. If this pattern mirrors the one on pin 2, the smart charge part of the alternator is faulty, and a new unit is required.
Martin
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